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Revision 812788aa

ID812788aa5bc592cf417de345fdd8a74933d7a0c8
Parent 0e77683c
Child cc9ca04e

Added by Thomas Mullins almost 4 years ago

Moved some sensors to different timers

Most notably, change the ROS millisecond counter to share the BOM 38 kHz
timer instead of having its own. The range sensor and BOM rx will now
share timer 5, but they both have to be fixed for the higher F_CPU.

View differences:

scout_avr/src/bom.cpp
12 12
 *   0: 1ms period
13 13
 *  Signal:
14 14
 *   38kHz pulse for 320us, then off for rest of time (680us or 1680us)
15
 * BOM uses timer 4 for period timing, and timer 3 for 38kHz signal
15
 * BOM uses timer 4 for period timing, and timer 0 for 38kHz signal
16 16
 */
17 17

  
18
#define TIME_KHZ(khz, prescale) (F_CPU / 1000 / (khz) / (prescale))
19 18
#define TIME_MICROS(us, prescale) (F_CPU / 1000000 * (us) / (prescale))
20 19

  
21 20
typedef uint16_t sharp_msg_t;
......
52 51
  return robot_id;
53 52
}
54 53

  
55
ISR(TIMER3_COMPA_vect) {
54
void bom_isr() {
56 55
  if (out_high) {
57 56
    BOM_EMIT ^= out_pin_mask;
58 57
  }
......
62 61
  out_high = 0;
63 62
  out_pin_mask = 0;
64 63
  
65
  // timer 3 mode CTC (clear timer on compare), TOP = OCRA
66
  TCCR3A = 0;
67
  TCCR3B = _BV(WGM32);
68
  TCCR3C = 0;
69
  
70
  // toggling at 38kHz * 2 gives 38kHz wave
71
  OCR3A = TIME_KHZ(38 * 2, 1);
72
  
73
  // enable interrupt
74
  TIMSK3 = _BV(OCIE3A);
75
  
76
  // start timer 3 at F_CPU, no prescaling
77
  TCCR3B |= _BV(CS30);
64
  // timer configuration now done in Atmega128rfa1.cpp
78 65
}
79 66

  
80 67
static void start_38kHz_signal() {
......
92 79
  // timer 4 mode CTC (clear timer on compare), TOP = OCRA
93 80
  TCCR4A = 0;
94 81
  TCCR4B = _BV(WGM42);
95
  TCCR3C = 0;
96 82
  
97 83
  // run interrupt immediately when timer started
98 84
  OCR4A = 0;
......
166 152
  if (is_rising) {
167 153
    // TODO check 320us? or have 320us timeout on rising edge?
168 154
  } else {
169
    // uses timer 1, assuming prescale 1/8
170
    // timer 1 is set up by range_init()
155
    // uses timer 5, assuming prescale 1/8
156
    // timer 5 is set up by range_init()
171 157
    // this should be in units of microseconds
172
    int now = TCNT1 * (F_CPU / 1000000 / 8);
158
    int now = TCNT5 / (F_CPU / 8 / 1000000);
173 159
    
174 160
    if (rx->count) {
175 161
      int diff = now - rx->last_time;

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